Nanolipoprotein particles (NLPs) and other particles of nanoscale dimensions have been developed to support and carry target molecules.
In particular, a number of research groups have prepared recombinant high density lipoprotein particles (rHDL) as a cell membrane mimetic for incorporating membrane proteins—the latter consist of a hydrophobic moiety or membrane interacting region that associates with the nonpolar region of the lipid bilayer and portions that are hydrophilic and extend to both the interior and exterior regions.
According to this approach the target molecule is anchored to the nanolipoprotein particle through the hydrophobic moiety that is embedded within the lipid bilayer. The resulting molecular complex relies wholly on nonpolar interactions for stability in an overall aqueous environment.
In view of the above, incorporation of molecules which do not present a hydrophobic moiety for interaction within the lipid bilayer has been virtually impossible. Also, in view of the need to rely on nonpolar interactions for inclusion of the target molecule and stability of the nanolipoprotein particle, development of a nanolipoprotein particle comprising more than one target molecule has been challenging as well.
Accordingly, use of nanolipoprotein particles in applications, such as development of immunogenic compositions or development of systems for delivery of drugs or contrast agents, that require the inclusion of other molecules of interests, particularly soluble hydrophilic molecules, where the particle would ideally serve as a universal platform for supporting and carrying one or more target molecules of diverse chemical nature, has been particularly challenging.